First-Principles Study of C-C Coupling Pathways for CO₂Electrochemical Reduction Catalyzed by Cu(110)

To build a carbon-neutral energy cycle, the development of electrocatalysts that can reduce CO2 into products containing at least two carbon atoms (C2+) is crucial. This process would require at least one C-C coupling of two C1 intermediates. The (110) facet of copper is known for its ability to reduce CO2 to C2+ products in high quantities (Faradaic efficiency ≥65%). In this study, we used constant electrode potential density functional theory calculations to determine the dominant C-C coupling pathways for CO2 electrochemical reduction (CO2ER) on Cu(110). By studying the mechanism of CO2ER to methane, we identified *CO and *CH as high-concentration C1 species due to their high ΔG‡ for further hydrogenation. Based on this result, 26 C-C coupling reactions that contain at least one high-concentration C1 intermediate were selected for investigation. The most important ones responsible for C2+ formation on Cu(110) were identified, and the influence of strain on the rates of these reactions was also investigated.